In Task Area 1, an oscillating quartz viscometer was developed to measure viscosities of CO/sub 2//hydrocarbon systems over a range of conditions. Viscosity dependency on density, composition, and temperature is examined and the functional form of a modified Lohrenz, Bray, and Clark correlation for CO/sub 2/-oil systems is presented. Also, the effect of free gas on displacement efficiency and that of multiple hydrocarbon phase flow on sweep efficiency are being investigated. With two-dimensional glass micromodels at reservoir conditions, we studied the effects of different scales of microscopic heterogeneity on flow behavior and blocking mechanisms using both in-situ foaming and pregenerated foam. Additionally, the initial formulation of a two-dimensional simulator which models high-pressure gas-foam flow is presented. A simulation of the processes of high-permeability zone blockage with foam, fluid diversion, and increased trapped oil recovery is included. Also, an NMR imaging study on fluid flow through porous media addressing the nonlinear stability analysis of miscible displacements and matrix-fracture fluid transport functions has been initiated. In Task Area 2, work commenced on the non-uniformity of flow which results from rock heterogeneity. Emphasis was placed on the effect of this non-uniformity on displacement efficiency. Measurements were made of the steady-state mobility of foam-like dispersions of dense CO/sub 2/ in surfactant solutions. 114 refs., 138 figs., 21 tabs.